Why would you just want to raise your oil pressure? The only thing that could cause is your oil pump to wear faster, your cylinder walls to receive no cooling and lubrication, and loss of power due to restricted oil flow... It's not the pressure of the oil in the crank bearings that lubricate them, it's the movement of oil over them. If you wanted to increase oil flow, you could fit an oil bypass valve with a higher release pressure. By restricting oil flow, all you're doing is causing the bypass valve to pop open at a lower RPM. This means that from that RPM and up, the oil pressure has reached max; thus your oil flow remains constant even though the revs are rising. Bad.